Thermoplastic polymers have long been used in the preparation of brush bristles. Such bristles have been prepared in a wide variety of configurations, including solid and hollow monofilaments, and a variety of cross sectional shapes including circular, oval, triangular and lobate. These polymeric bristles have provided advantages over natural bristles such as hogs hair in both cost and performance. Polymeric bristles are often tapered to provide a large diameter end which is contained within the ferrule of the brush while presenting a smaller diameter at the tip of the paintbrush.
Polymeric paintbrush bristles are generally subjected to an abrasive treatment that results in the raising of flags on the surface of the bristle. The flags, in turn, increase the ability of the bristle to hold paint. Accordingly, efforts have been made in the past to prepare a polymeric paintbrush bristle that was particularly amenable to flagging. Other attempts at improving polymeric brush bristles have included modification of the cross-sectional configuration of the filament to reduce the tendency to curl and improve resistance to crushing of hollow filaments.